vm被systemd删除

qemu-kvm: terminating on signal 15 from pid 2146 (/usr/sbin/libvirtd)  这是正常情况
qemu-kvm: terminating on signal 15 from pid 1 (/usr/lib/systemd/systemd)    一开始不清楚qemu-kvm被systemd终止是发生在什么情况下？

[root@EXTENV-194-18-2-14 ~]# systemctl status openvswitch
● openvswitch.service - Open vSwitch
   Loaded: loaded (/usr/lib/systemd/system/openvswitch.service; enabled; vendor preset: disabled)
   Active: inactive (dead)

Apr 11 10:48:20 EXTENV-194-18-2-14 systemd[1]: Dependency failed for Open vSwitch.
Apr 11 10:48:20 EXTENV-194-18-2-14 systemd[1]: Job openvswitch.service/start failed with result 'dependency'.

# vim /var/log/neutron/openvswitch-agent.log
2018-04-11 10:40:05.512 2726 ERROR neutron.agent.linux.async_process [-] Error received from [ovsdb-client monitor tcp:127.0.0.1:6640 Interface name,ofport,external_ids --format=json]: None
2018-04-11 10:40:05.513 2726 ERROR neutron.agent.linux.async_process [-] Process [ovsdb-client monitor tcp:127.0.0.1:6640 Interface name,ofport,external_ids --format=json] dies due to the error: None

# getenforce
Enforcing

# setenforce 0
# getenforce
Permissive
# systemctl restart openvswitch
# systemctl status openvswitch
● openvswitch.service - Open vSwitch
   Loaded: loaded (/usr/lib/systemd/system/openvswitch.service; enabled; vendor preset: disabled)
   Active: active (exited) since Wed 2018-04-11 11:17:20 CST; 5s ago
  Process: 4479 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 4479 (code=exited, status=0/SUCCESS)

# ll /etc/sysconfig/selinux
lrwxrwxrwx. 1 root root 19 Apr 11 09:23 /etc/sysconfig/selinux -> /etc/selinux/config